John Oliver used his last Game of Thrones lead-in to discuss death. "Specifically, this story is about the people who investigate deaths when they happen," he explained on Sunday's Last Week Tonight. "And if you're thinking, 'I don't want to see that on TV,' are you completely sure about that? Because death investigators aren't just supporting characters on some of the most popular shows."

"In real life, every year about 2.8 million Americans die," Oliver said, and while doctors identify cause of death on most death certificates, "if someone dies under suspicious or unnatural circumstances, their body may be sent for further examination and possibly a forensic autopsy. That's what happens to about a half a million bodies each year, and those investigations are incredibly important. A death certificate isn't like a degree from USC — it actually means something." Autopsies are important in murder investigations, but they also highlight trends in drug deaths, help identify defective products, and warn of infectious disease outbreaks.

"So tonight, let's learn about our death investigation system, specifically how it works, why it's such a mess, and what we can do about it," Oliver said. First, medical examiners and coroners aren't synonymous — medical examiners must be doctors, coroners are often elected, with shockingly few qualifications. That's "frankly weird enough," he said, but "in some jurisdictions, the coroner is also the county sheriff, and that has led to some serious problems."

The medical examiner system is better, but there are problems there, too, Oliver said. "The resources crunch is so bad that some offices wind up outsourcing work to private contractors, and this is where this story gets absolutely incredible." He focused on one contractor. "Look, I know this issue is tempting to ignore — it combines two things that people hate thinking about the most: Death and municipal funding," he said. But he tried to make it palatable, roping in Beyoncé, Glenn Close's spleen, and Tracy Morgan. (There's NSFW language.) Peter Weber

If we're to save the Earth from a climate-related catastrophe in 21 years, we need to take drastic action, and one proposal getting discussed a lot is the Green New Deal, John Oliver said on Sunday's Last Week Tonight. "The Green New Deal has been famously polarizing. On one hand, all the senators running for president co-sponsored it; on the other hand, Republicans have been foaming at the mouth to criticize it for all the crazy provisions that they insist it contains," like bans on hamburgers and airplanes.

"The first thing to understand is that the Green New Deal doesn't even mention the word 'cows' or 'airplanes,'" or even "specific programs to fight climate change," Oliver explained. "It is a nonbinding resolution that very briefly sets out some extremely aggressive goals," and the whole thing "is just 14 pages long — that is, seven pages shorter than the menu for The Cheesecake Factory."

The Green New Deal's main proponent, Rep. Alexandria Ocasio-Cortez (D-N.Y.), rightly "admits the rollout of the Green New Deal was 'the biggest mistake' she's made in Congress," largely because she released a draft Q&A that contained what's "clearly supposed to be a joke" about getting rid of "farting cows and airplanes," Oliver said, thus allowing certain named "idiots to pretend the Green New Deal was all about hamburger-stealing."

"But while the rollout of this conversation has been bumpy, it is great that the Green New Deal has started one," Oliver said. "No one solution is going to be nearly enough" to combat climate change, and there are lots of ideas. Oliver focused on, and explained, carbon pricing. "Look, I know that this can all seem hopeless, especially under the current administration, but there are actually some small signs that the tide may be turning here," he said. Watch to the end to see "gritty reboot" Bill Nye drop F-bombs and set the world on fire. Peter Weber

With just three episode left of "the greatest lead-in modern television history," Game of Thrones, "I'm burning one of them on lethal injections," John Oliver said on Sunday's Last Week Tonight. "And the reason I'm doing that is it's a subject that doesn't come up very much, because, frankly, no one wants it to." From his description of lethal injections, it wouldn't be out of place on Game of Thrones.

Oliver conceded that there are sharp — sometimes odd — differences in opinion on the death penalty, and he explained why he believes it shouldn't exist, using a NSFW example. But "let's say you support the death penalty — there's still the question of how you do it," he said. "Lethal injection came into vogue because it was seen as a humane and painless method," at least compared with "the horrors inflicted by the electric chair." It isn't.

First, doctors refused to help design the lethal three-drug cocktail, and they won't help administer it, for pretty obvious reasons, Oliver said. "Hippocrates didn't say: 'First, do no harm. Second, do some harm.'" He also explained why the first drug really matters, why states are now using a woefully inadequate alternative — Midazolam — and why the main expert witness on Midazolam isn't an expert.

Lethal injection is botched so often — Oliver described one case — that two death row inmates in Tennessee opted for the electric chair last year. "So incredibly, in our desire to find a more humane method, we've ended up letting amateurs both invent and administer a form of unpredictable torture," he said. "The fundamental fact to remember about lethal injection is it is a show; it is designed not to minimize the pain of people being executed, but to maximize the comfort of those who want to support the death penalty without confronting the reality of it." He ended back with his NSFW example and a grim punch line. Watch below. Peter Weber

Last Week Tonight was off the air this week, but John Oliver posted a video Sunday from last week's show. It was a sort of love story. "Japan — there is something amazing happening over there right now," he began. This "something" involves Chiitan, an unsanctioned Japanese municipal mascot — an otter with a turtle as a hat — that describes himself as a "0-year-old fairy baby" who "plays around super actively every day!" Oliver was a fan. "Every Chiitan video is a work of art," he said, and he waxed poetic about the mascot's tweets.

"When's the last time Twitter made you happy?" Oliver asked, fairly. "When's the last time anything made you happy?" Because this is John Oliver, and because he has HBO money, the Chiitan saga took several bizarre turns. If you want a fleeting moment of happiness and don't mind NSFW language, you can watch it all unfold below. Peter Weber

John Oliver's main story on Sunday's Last Week Tonight focused on — what else? — Special Counsel Robert Mueller's report, which he framed as the latest and maybe last chapter of his "Stupid Watergate" series — "basically Watergate, but if Nixon had been kicked in the head by a billy goat, and also if that billy goat had been the White House chief of staff."

Once people actually read the 448-page redacted report released Thursday, "it became clear that there was a lot in it," Oliver said. "And some of the details in this report were incredible." The one he lingered on, with artistic license, was Trump reportedly saying Mueller's appointment marked "the end of my presidency, I'm f---ed" — except Oliver, of course, did not censor the F-word. Since "we clearly can't cover everything in the report tonight," he said, "I'd like to concentrate on two key factors that may have saved the president here": Incompetence and disobedience.

"When it comes to conspiracy, Trump's saving grace may have been that despite Russians wanting to help," his campaign and family displayed "often cartoonish levels of disorganization and incompetence," plus "ignorance of basic legal concepts," Oliver said. He said the report's findings that so many of the people in Trump's orbit just ignored his orders to potentially obstruct justice is "both reassuring and also terrifying," though worryingly, "lots of those people are gone now, and the newer figures seem very much on the same page as the president," notably Attorney General William Barr.

Barr's preemptive spin now "seems laughably and willfully misleading," Oliver said. "It's like Barr summarized the Twilight novels as: 'A girl in Florida goes to third base with a wookie.'" The parts of Mueller's report we can read may feel like a letdown, he said, but its imparted knowledge "can inform Congress going forward and, crucially, voters a year and a half from now." The clip is full of NSFW language. Watch below. Peter Weber

The opioid epidemic "is very much ongoing" but "we've learned a lot more about many of the companies involved" since Last Week Tonightlast covered the issue in October 2016, John Oliver said Sunday night. The first chapter of the opioid crisis turns out to be "a story of how major companies acted wildly irresponsibly, skirted any meaningful consequences, and for the most part, avoided public scrutiny," he said. "For companies involved in the opioid crisis, fines just became the cost of doing business, and throughout this crisis it has been difficult to find any real accountability for the people involved."

Oliver focused on Richard Sackler, the near-invisible heir who was company president when OxyContin went viral. "This invisibility feels deliberate, and whether it is or not, it has definitely been convenient for Richard Sackler, because it's honestly hard to tell the story of his time at Purdue without any video," Oliver said. "To help you get the emotional impact of Richard Sackler's actual words, we got an actor to play him."

Four actors, it turned out, starting with Michael Keaton (because "when you're casting for a shadowy heir to a vast fortune who doesn't like to be in the limelight, you go Batman") plus including Bryan Cranston, Richard Kind, and Michael K. Williams. The Sacklers and Purdue deny causing the opioid crisis and say Sackler's comments were taken out of context, Oliver said dutifully. To add context, he had the actors read parts of Richard Sackler's emails and a newly leaked deposition, both on the show and at SacklerGallery.com. Oliver pitched it as an incentive for the Sacklers to release video of Richard Sackler. (There is NSFW language throughout the video.) Peter Weber

"There are many misconceptions about mobile, or 'manufactured,' homes," John Oliver said on Sunday's Last Week Tonight. For example, "it can be genuinely hard to tell the difference between manufactured homes and conventional homes," and about 20 million people in the U.S. live in what has been "one of America's last affordable housing options," kind of.

Recently, private equity firms and other large investors are jumping in, he added. "So the homes of some of the poorest people in America are getting snapped up by some of the richest people in America, and luckily, there have been no problems whatsoever — except I'm obviously kidding, it's going terribly."

"The rise of big-money investors in mobile homes has led to a corresponding spike in rents, fees," and other costs, Oliver said. High-interest financing by leading manufactured-home seller Clayton Homes, controlled by Warren Buffett but advertised by Duck Dynasty's Phil Robertson, is one reason mobile homes are a great investment for big investors, and a lousy one for buyers, Oliver said, but it's not the only reason.

About a third of mobile home dwellers own their house but not the land it sits on, and the large investors snapping up mobile home parks tend to jack up rents or tear down the parks. In fact, 80 percent of mobile homes never move, Oliver said, "and this lack of mobility for tenants is actually part of the attraction for big investors," some of whom are openly "cynical and predatory" about their motives — Oliver singled out one man.

One solution is for residents of mobile home parks to band together and buy their own park, and some nonprofits facilitate this process. But everyone needs to know the potentially "financially catastrophic" risk of buying a mobile home on land you don't own, Oliver said. He helped out by making an ad, starring The Good Place's Janet (D'Arcy Carden) as an unsatisfied customer. There is NSFW language sprinkled throughout. Peter Weber

John Oliver didn't have too much to say about Special Counsel Robert Mueller's report on Russian election meddling and possible malfeasance by President Trump's campaign, mostly because almost nobody has seen that report. "We only know what Trump's own attorney general thinks we need to know," he said on Sunday's Last Week Tonight, and William Barr is a suspect source. Despite the ostentatious victory lap by Trump's supporters and Fox News friends, however, there's plenty of bad news even in Barr's four-page summary.

Mueller's "report did not establish a criminal conspiracy between Russia and Trump's campaign, which is undeniably good news for the president," Oliver said. But "Trump was not completely exonerated. In fact, the report literally says it 'does not exonerate him.' The only way Mueller could have been clearer on that point is if he put hand-clap emojis between every word." Ordinarily, such news "might prompt headlines like 'President May Have Obstructed Justice,'" he said, but news organizations, like Trump's supporters, took "one piece of good news and rounded it up to two."

"Even if the investigation didn't conclude that Trump conspired with the Russians, that doesn't mean the whole thing was a waste of time," Oliver said. "Just for a moment, try and imagine that it all came out at once, and there was a single headline that said: 'Russia Confirmed to Have Interfered in Election, and President's Campaign Manager, Lawyer, Multiple Advisers Convicted of Crimes, and Trump and His Team Lied About Business With Russia, Contact With Russians, and Trump May Have Committed Campaign Finance Violations to Cover Up Affair With Adult Film Star Shortly After His Wife Gave Birth, and Which He Also Attempted to Continue But Ended Up Sitting Next to the Adult Film Star in a Hotel Room and Watching Shark Week.' Because all of that happened. And we know it one way or another as a result of Mueller's investigation." Watch below. Peter Weber